Abstract:

This paper presents the sensitivity evaluation of an optical receiver in Distributed Fiber Temperature Sensor (DTS) based on Raman Backscatting whose energy is very weak in nW. First, the noise of the optical receiver is studied; a calculation formula of SNR is got, which is directly determined by the thermal noise. Then calculation and analysis show the relationship between the effective bit of the AD converter and accumulation number, and point out that the quantization error decreases with the increase of accumulation number while the effective bit of the AD converter will increase. At last, the authors put forward the calculation formula of the sensitivity evaluation of the optical receiver. Using this method, it 's very easy to calculate the temperature resolution of DTS and valuable to the analysis and design of this kind of sensor system.

Key words: op t ical receiver, sensit ivity, temperature, signal to no ise rat io